Sometimes women have more bleeding then they would think with implantation. Everyone is different. So be hopeful. BUT don't test till your period is late.
Hey, i too am due for AF within a few days of you, 23rd i think im due. Anyway, its very possible it was heavier then usual implantation bleed, but again, you could of ovulated much earlia, and so therefore it could be AF gearing up to show her face!! I know how frustrating it is TTC (trying to concieve)..ive been trying since December 2009 since a miscarriage at 6 weeks! I would wait it out for the day your period is due, then take a test!!